System and method for insulating and shielding a heated tank car

ABSTRACT

A railway tank car includes a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed end. A plurality of heat transfer ducts operable to receive a heating fluid may be disposed on a lower portion of an exterior surface of the tank. A layer of ceramic coating may be disposed over exterior surfaces of the plurality of heat transfer ducts and at least a portion of the exterior surface of the tank.

RELATED APPLICATION

[0001] This application claims the benefit of previously filed provisional application entitled “Super Capacity/Payload Tank Car with Enhanced Heating System,” Serial No. 60/300,647, filed Jun. 25, 2001.

TECHNICAL FIELD

[0002] The present invention is related to heated tank cars and related components, and more particularly to a system and method for increasing capacity of a heated tank car.

BACKGROUND OF THE INVENTION

[0003] Railway tank cars may be used to move hazardous and non-hazardous liquid or semi-liquid bulk freight of all types including, but not limited to: liquefied petroleum gases; liquefied gases (e.g., carbon dioxide); chemical intermediates; polymers; antiknock compounds; anhydrous ammonia; chlorine; alcohol; vegetable and fish oils; fruit juices; wine and syrups. Many of the tank cars currently in use can carry in excess of one hundred tons and often have a thirty-thousand gallon capacity. Tank cars that are heated, pressurized, internally lined, or a combination of these features, are available to shippers.

[0004] Heated tank cars may be used to carry liquids that require infrequent heating and are highly viscous, or liquids that have phase changes at low temperatures. Heating systems including heating panels, internal pipes, and heating ducts or coils may be applied within and/or external to the tank car in order to increase the temperature of the lading during loading or unloading operations. These panels, ducts, coils or pipes may be fed by a heating fluid such as steam, hot water, hot oil, or other suitable heating media.

[0005] Heated tank cars often include an insulating material disposed over the heating systems. The insulating material may be approximately four inches thick. In some heated tank cars, the insulating material is covered by a steel jacket, which typically has a minimum thickness of 11 gauge.

SUMMARY OF THE INVENTION

[0006] In accordance with teachings of the present invention, disadvantages and problems associated with previous heating systems for railway tank cars have been substantially reduced or eliminated. More specifically, a layer of ceramic coating is provided upon the heating system and adjacent components of a tank car to increase the efficiency of the heating system and protect or safe-guard individuals that come in contact with the tank car. The insulation is applied sparingly in order to reduce weight and increase the payload capacity of the tank car.

[0007] In one embodiment of the present invention, a railway tank car includes a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed end. A plurality of heat transfer ducts are disposed on a lower portion of an exterior surface of the tank and may be operable to receive a heating fluid. A layer of ceramic coating is disposed over exterior surfaces of the heat transfer ducts.

[0008] In another embodiment, a railway tank car includes a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed. The tank car also includes one or more heater panels, each having an interior surface, an exterior surface, and a plurality of dimples. Each heater panel may be coupled to an exterior or interior surface of the tank by the plurality of dimples such that one or more ducts operable to receive a heating fluid are formed between each heater panel and the tank. In addition, a layer of ceramic coating may be disposed on the exterior surface of each heater panel.

[0009] In yet another embodiment, a method of insulating a railcar heating system includes providing a railway tank car including a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed end. A plurality of heat transfer ducts are disposed on an exterior surface of the tank and are operable to receive a heating fluid. The method further includes forming a layer of ceramic coating over exterior surfaces of the heat transfer ducts.

[0010] Various embodiments of the present invention may benefit from numerous technical advantages. It should be noted that one or more embodiments may benefit from some, none, or all of the advantages discussed below.

[0011] One technical advantage includes a shielding system that reduces the chance of personnel working on or around the tank car from being burned or otherwise injured by the heating system.

[0012] Another technical advantage includes a shielding system that can be used in connection with any type of heating system using heating coils or ducts, including conventional and enhanced heating systems.

[0013] Yet another technical advantage includes a shielding system that is dimensionally small and lightweight and thus contributes little to the overall size and weight of the tank car as compared to traditional insulation systems. The carrying capacity of the heated railcar can thus be increased as compared to heated railcars having traditional insulation systems. In addition, the combination of the heating characteristics (such as the amount of heat transfer or the efficiency) and the physical characteristics (such as the size, weight, capacity or payload) of the tank car contribute to a more efficient and/or safer operation of the tank car.

[0014] Still another technical advantage includes a shielding system that may be easily applied to a new tank car or adapted to an existing tank car. In particular, in some embodiments, insulation such as ceramic coating may be sprayed over heating system components after the jacket, insulation, and other components of the existing insulation system are removed.

[0015] Still another technical advantage includes a shielding system that provides thermal insulation of heating system components, such as ducts or coils, that may become heated during operation of the heating system. This decreases the amount of heat that is transferred from the heating system to the ambient surroundings and increases the amount of heat that is transferred from the heating system to the inside, and thus to the contents, of the tank of the railway tank car. Accordingly, the efficiency of the heating system is enhanced.

[0016] Still another technical advantage includes a heat transfer system that may be coupled to the inside or outside of the tank to increase the amount of heat transfer from the heating system to the inside of the tank, and thus to the contents of the tank. The heat transfer system may include a heat transfer member that has a larger than normal surface-to-volume ratio and may be configured such that a relatively large surface area transfers heat to the inside of the tank.

[0017] Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] A more complete and thorough understanding of the present embodiments and advantages thereof may be acquired by referring to the following description, taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein:

[0019]FIG. 1 is a schematic drawing illustrating a side view of a railway tank car having a heating system and a shielding system in accordance with an embodiment of the present invention;

[0020]FIG. 2 is a schematic drawing illustrating an end view of the railway tank car of FIG. 1;

[0021]FIG. 3 is a schematic drawing with portions broken away, illustrating a cross-sectional view of a tank, a heating system, and a shielding system including a shielding layer covering the heating system and adjacent portions of the tank;

[0022]FIG. 4 is a schematic drawing with portions broken away, illustrating a cross-sectional view of a heating system and a shielding system including a shielding layer and a protective covering over a heating system, with gaps formed between the shielding layer and the protective cover;

[0023]FIG. 5 is a schematic drawing with portions broken away, illustrating a cross-sectional view of a heating system and a shielding system including a shielding layer and a protective covering supported by protective covering supports;

[0024]FIG. 6 is a schematic drawing with portions broken away, illustrating a cross-sectional view of a heating system and a shielding system;

[0025]FIG. 7 is a schematic drawing with portions broken away, illustrating a cross-sectional view of a heat transfer member coupled to an interior surface of a tank;

[0026]FIG. 8A is a schematic drawing illustrating a three-dimensional view of an alternate heater panel system;

[0027]FIG. 8B is a schematic drawing with portions broken away, illustrating a cross-sectional view of a heating system formed by the heater panel of FIG. 8A coupled to the exterior of a tank; and

[0028]FIG. 9 is a schematic drawing with portions broken away, illustrating a cross-sectional view of a heating system formed by a heater panel coupled to the interior of a tank.

DETAILED DESCRIPTION OF THE INVENTION

[0029] Many railway tank cars include heating systems for heating the contents of the tank. These heating systems may cause injuries, particularly burn injuries, to personnel working on or around the tank car. In addition, a large portion of the heat generated by such heating systems may be lost to the surrounding ambient environment rather than being transferred to the lading inside the tank car. Current methods of protecting personnel and insulating the tank cars significantly increase the size and weight of the tank car, thereby decreasing the carrying capacity or maximum payload of the tank car.

[0030] Thus, a shielding system is provided that includes at least one shielding layer, such as ceramic coating, disposed over components of the heating system and at least a portion of the exterior of the tank. The shielding layer may be sprayed on and may be applied sparingly to minimize the added size and weight of the tank car. The shielding system may also include a protective covering or a heat shield installed over the layer of insulation or directly over the components of the heating system. In general, the shielding system enhances the efficiency of the heating system and protects personnel working on or near the tank car.

[0031] Referring to FIGS. 1 and 2, a railway tank car 10 includes a tank 12, a heating system 50, and a shielding system 70. Tank 12 may include a generally elongated hollow cylinder 18 enclosed at a first end 20 and a second end 22, a first side 24 and a second side 26, an upper portion 28 and a lower portion 30, and an interior surface and an exterior surface 32.

[0032] Tank car 10 may be used to transport a variety of hazardous and non-hazardous liquid or semi-liquid bulk commodities of all types. Liquid commodities may be loaded within tank 12 through a variety of tank fittings such as a manway 38. Unloading of the commodities, or lading, may be accomplished through a variety of fittings, such as a discharge valve 40. In other embodiments, discharge valve 40 may be located virtually anywhere on tank 12, for example, at upper portion 28 or proximate first end 20 or second end 22 of tank 12. In addition, tank 12 may be pressurized to assist in the unloading of the lading. Further, the shape and/or configuration of tank 12 may also assist in unloading the lading. For example, tank 12 may slope gradually at lower portion 30 from each end 20 and 22 toward discharge valve 40. The configuration and slope of upper portion 28 of tank 12 may conform to the configuration and slope of the lower portion 30. A head 42 is coupled to cylinder 18 at first end 20. Similarly, a head 44 is coupled to cylinder 18 at second end 22. Cylinder 18 and heads 24 and 26 at least partially define tank 12 and protect the contents of tank 12 from the ambient environment.

[0033] Heating system 50 may be used to heat the contents of tank 12. In particular, heating system 50 may be used to heat lading which is highly viscous at low temperatures in order to unload the lading efficiently through discharge valve 40. Heating system 50 may also be used to prevent liquid lading from freezing in low temperatures. Shielding system 70 provides thermal insulation and physical protection of components of heating system 50, as discussed below in greater detail.

[0034] Heating system 50 may include one or more inlets 52, heat transfer ducts (or coils) 54, and outlets 58. Heat transfer ducts 54 may include one or more supply ducts and one or more return ducts. In the embodiment shown in FIGS. 1 and 2, heating system 50 includes an inlet 52 and a plurality of heat transfer ducts 54 located on each side 24 and 26 of tank 12, although only the first side 24 is shown in FIG. 1. In this embodiment, inlet 52 is coupled to a heat transfer duct 54 located along the centerline of the lower portion 30 of tank 12. In addition, heating system 50 includes an outlet 58 that is shared by the portions of heating system 50 located on each side 24 and 26 of tank 12.

[0035] In general, heat transfer ducts 54 may be used to transport a heating fluid through heating system 50. As used in this document, the term “heating fluid” includes steam, hot water, hot oil, or any other suitable heating media.

[0036] In particular, with regard to the portion of heating system 50 located on first side 24 of tank 12, the heating fluid enters heating system 50 through inlet 52. The heating fluid then travels along heat transfer ducts 54 in the direction of the arrows shown in FIG. 1, turning at a plurality of elbows 60 that couple heat transfer ducts 54 to each other. The heating fluid exits heating system 50 through outlet 58. When steam is used as the heating fluid, the steam may change into condensate at some point within heating system 50. In such situations, the condensate may be discharged from heating system 50 through outlet 58.

[0037] Heating system 50 may include any suitable number of inlets 52, heat transfer ducts 54, and outlets 58. In some embodiments, heating system 50 includes at least two heat transfer ducts 54 disposed on each side 24 and 26 of tank 12. In a particular embodiment, heating system 50 includes three heat transfer ducts 54 disposed on each side 24 and 26 of tank 12. In another particular embodiment, such as shown in FIG. 1, heat system 50 includes six heat transfer ducts 54 disposed on each side 24 and 26 of tank 12 and one heat transfer duct 54 disposed along the centerline of the bottom 30 of tank 12. In some other embodiments, heating system 50 includes at least seven heat transfer ducts 54 disposed on each side 24 and 26 of tank 12. In a particular embodiment, heating system 50 includes seven heat transfer ducts 54 disposed on each side 24 and 26 of tank 12.

[0038] In addition, heating system 50 may include more than one group of heat transfer ducts 54 on each side 24 and 26 of tank 12. In particular, heating system 50 may include a first group of heat transfer ducts 54 extending longitudinally from a location proximate a longitudinal midpoint of tank 12 to a location proximate first end 20 of tank 12, and a second group of heat transfer ducts 54 extending longitudinally from another location proximate the longitudinal midpoint of tank 12 to a location proximate second end 22 of tank 12. In one embodiment, heating system 50 includes two such groups of heat transfer ducts 54 on each side 24 and 26 of tank 12.

[0039] Shielding system 70 provides thermal insulation to, and physical protection from, components of heating system 50 that may become heated during operation of heating system 50, such as heat transfer ducts 54. In general, shielding system 70 is disposed over components of heating system 50 and at least a portion of tank 12. In some embodiments, shielding system 70 is disposed over all or substantially all of tank 12. In one embodiment, shielding system 70 is disposed over all or substantially all of the tank car 10, including tank 12, supporting structures, fittings, safety devices, and/or other components of tank car 10. In another embodiment, shielding system 70 is disposed only over components of heating system 50 and adjacent portions of tank 12, rather than over the entire tank 12. In this embodiment, the exterior surface 32 of the upper portion 28 of tank 12 may be substantially free of the shielding system 70. In yet another embodiment, shielding system 70 is disposed over the entire tank 12, but has a greater thickness in areas proximate heating system 50.

[0040] Shielding system 70 provides the advantage of insulating, shielding, and protecting tank car 10 from the environment while adding little to the overall size and weight of tank car 10, which is important because the payload capacity, weight, and dimensions of railcars are regulated by the U.S. Department of Transportation. For example, since some embodiments of shielding system 70 are smaller than traditional insulation systems, such as those with insulation covered by an 11 gauge or thicker metal jacket, the diameter of the tank to which shielding system 70 is applied may be increased without exceeding the maximum regulated dimensions. Thus, in some embodiments, a shorter tank may be used to carry the same payload due to the increased diameter of the tank. In some embodiments, as a result of the decreased size and weight of shielding system 70, the carrying capacity of the railcar can be increased as compared to railcars having traditional insulation systems. For example, in some embodiments, the carrying capacity of a railcar 10 using shielding system 70 may be 5,000 to nearly 9,000 pounds greater than a similar railcar 10 using a traditional insulation system.

[0041] In addition, shielding system 70 reduces the risk of personnel working on or around tank car 10 from being burned or otherwise injured by heating system 50. In particular, the exterior surfaces of shielding system 70 will generally remain cooler than the exterior surfaces of the components of heating system 50 when heating system 50 is in operation. Shielding system 70 also protects components of tank car 10, including heating system 50, from being damaged by environmental conditions around tank car 10. For example, shielding system 70 generally includes one or more layers of protection, such as a layer of liquid ceramic coating, a protective cover, and/or a heat shield, each of which add additional protection for the components of tank car 10 from the environment.

[0042] Shielding system 70 may also be easy to install or apply to tank car 10. For example, in some embodiments, a layer of ceramic coating is sprayed directly onto the components of heating system 50. In addition, in some embodiments, applying insulation over the entire tank car 10 eliminates the need to apply a separate and different finish coat for protecting upper portion 32 of tank 12 from the environment.

[0043] Further, shielding system 70 enhances heating system 50. In particular, without shielding system 70, much of the heat generated by heating system 50 would be lost to the ambient surroundings of tank car 10, which may significantly reduce the temperature of the heating fluid within heating system 50. With shielding system 70, less heat is lost to the ambient surroundings and the heating fluid is thus kept at a higher temperature for a longer period of time, which increases the amount of heat that is transferred from the heating fluid to the contents of tank 12. Thus, the efficiency of heating system 50 is increased.

[0044]FIGS. 3 through 6 illustrate several example embodiments of shielding system 70, which are designated as shielding systems 70 a through 70 d. FIG. 3 is a partial cross-section of a tank 12 a and a heating system 50 a of a railway tank car, which is similar to tank 12 and heating system 50 of tank car 10. In addition, FIG. 3 illustrates one embodiment of shielding system 70, indicated as shielding system 70 a. Heating system 50 a includes a plurality of heat transfer ducts 72, such as heat transfer ducts 54 discussed above, coupled to an exterior surface 74 of tank 12 a. It should be noted that only one side of tank 12 a is shown, and thus although three heat transfer ducts 72 are shown in FIG. 3, heating system 50 a may also include three heat transfer ducts 72 coupled to the other side of tank 12 a.

[0045] Shielding system 70 a includes a shielding layer 80 disposed over the exterior surfaces 78 of heat transfer ducts 72 and at least a portion of exterior surface 74 of tank 12 a. Shielding layer 80 may include a liquid ceramic or a ceramic insulating coating (sometimes referred to as “ceramic insulation coatings”). Ceramic coatings are commercially available from various companies, such as Thermal-Coat™ manufactured by Capstone Manufacturing, having an office at 18225 47th Place NE, Seattle, Wash. 98155, or coatings manufactured by Insulating Coatings of America, having an office at 2854 E. Ponce de Leon Avenue, Decatur, Ga. 30030. In some embodiments, shielding layer 80 is formed by spraying (for example, with a spray gun) insulating or shielding material, such as liquid ceramic coating, over heat transfer duct 72 and tank 12 a.

[0046] Shielding layer 80 is generally disposed over heating system 50 a and at least a portion of tank 12 a. In some embodiments, shielding layer 80 is disposed over all or substantially all of tank 12. In one embodiment, shielding layer 80 is disposed over all or substantially all of tank car 10. In another embodiment, such as the embodiment shown in FIG. 3, shielding layer 80 is disposed only over components of heating system 50 a and adjacent portions of tank 12 a, rather than over the entire tank 12 a. In this embodiment, the exterior surface 32 of the upper portion 28 of tank 12 is substantially free of the shielding system 70 a.

[0047] Shielding layer 80 may be relatively thin as compared with conventional insulation systems, which may provide several advantages as discussed above. For example, in some embodiments, shielding layer 80 is less than 0.2 inches (200 mils) thick. In a particular embodiment, shielding layer 80 is approximately 0.1 inches (100 mils) thick. In another embodiment, shielding layer 80 is less than 0.1 inches (100 mils) thick.

[0048] In addition, in some embodiments, portions of shielding layer 80 proximate, or covering, heating system 50 a are thicker than portions of shielding layer 80 not proximate, or covering, heating system 50 a. For example, in some embodiments, the portion of shielding layer 80 covering heating system 50 a is less than 0.2 inches (200 mils) thick, whereas the remainder of shielding layer 80 is less than 0.05 inches (50 mils) thick. In a particular embodiment, the portion of shielding layer 80 covering heating system 50 a is approximately 0.1 inches (100 mils) thick, whereas the remainder of shielding layer 80 is approximately 0.016 inches (16 mils) thick. In another particular embodiment, the portion of shielding layer 80 covering heating system 50 a is less than 0.1 inches (100 mils) thick, whereas the remainder of shielding layer 80 is less than 0.016 inches (16 mils) thick.

[0049] One or more coating layers 81 may be disposed over all or portions of shielding layer 80. In some embodiments, one or more coating layers 81 cover all or substantially all of tank 12. Coating layers 81 may include exterior paint or other finishes, and may be corrosion resistant. For example, coating layer 81 may be a layer of epoxy paint covering all or substantially all of tank car 10. In one embodiment, coating layer 81 is a layer of epoxy paint having a thickness of approximately 0.004 to 0.006 inches (4-6 mils).

[0050] Shielding layer 80 may be applied directly to exterior surfaces 78 of heat transfer ducts 72 and/or exterior surface 74 of tank 12 a, or over one or more coating layers, which may be similar to coating layers 81 discussed above. In some embodiments, shielding system 70 a is applied after removing an existing insulation system, which may include a jacket, insulation, and/or other components, from a railcar. In addition, in some embodiments, shielding layer 80 is applied after removing an existing coating layer, such as external paint, from external surfaces 74 and/or 78. Thus, it should be understood that shielding system 70 a may be formed in connection with the assembly of heat transfer ducts 72 to tank 12 a or adapted to an existing railcar, which may include removing an existing insulation system and/or external coating.

[0051]FIG. 4 is a partial cross-section of a tank 12 b and a heating system 50 b of a railway tank car, which is similar to tank 12 and heating system 50 of tank car 10. In addition, FIG. 4 illustrates another embodiment of shielding system 70, indicated as shielding system 70 b. Similar to heating system 50 a shown in FIG. 3, heating system 50 b includes a plurality of heat transfer ducts 82 coupled to an exterior surface 84 of tank 12 b. And similar to shielding system 70 a shown in FIG. 3, shielding system 70 b includes a shielding layer 88 disposed over exterior surfaces 90 of heat transfer ducts 82 and over proximate or adjacent portions of exterior surface 84 of tank 12 b.

[0052] Shielding system 70 b further includes a protective covering 92 disposed over heat transfer ducts 82 and shielding layer 88. Protective covering 92 is supported by one or more supports 94 that may be welded, fastened or otherwise coupled to tank 12 b. One or more supports 94 may also be coupled to a sill 96 that is coupled to tank 12 b. This provides additional support for protective covering 92 and may ensure that components of heating system 50 a near the underside of tank 12 a are completely or substantially enclosed. Protective covering 92 may be made of one or more steel alloys, aluminum alloys, ceramic materials, cermets, fiber reinforced plastics, or any other suitable material. Protective covering 92 may be coupled to supports 94 by welding, fasteners, adhesives, or in any other suitable manner. Like shielding layer 88, protective covering 92 may be disposed only over components of heating system 50 b and adjacent portions of tank 12 b, rather than over the entire tank 12 b. Thus, in some embodiments, an upper portion of the exterior surface of tank 12 b is substantially free of protective covering 92.

[0053] Protective covering 92 provides additional insulation for heating system 50 b, which further increases the amount of heat transferred from heating system 50 b to the inside of tank 12 b, and also provides additional protection for personnel working on or near the tank car. In addition, protective covering 92 further protects components of heating system 50 b, as well as shielding layer 88, from damage caused by age, weather, personnel, or other factors.

[0054]FIG. 5 is a partial cross-section of a tank 12 c and a heating system 50 c of a railway tank car, which is similar to tank 12 and heating system 50 of tank car 10. In addition, FIG. 5 illustrates another embodiment of shielding system 70, indicated as shielding-system 70 c. Similar to heating system 50 b shown in FIG. 4, heating system 50 c includes a plurality of heat transfer ducts 122 coupled to an exterior surface 124 of tank 12 c. And, similar to shielding system 70 b shown in FIG. 4, shielding system 70 c includes a protective covering 128 disposed over exterior surfaces of heat transfer ducts 122 and over nearby or adjacent portions of exterior surface 124 of tank 12 c.

[0055] As shown in FIG. 5, protective covering 128 may be coupled to tank 12 c by one or more attachment devices 132. Attachment devices 132 may coupled to exterior surface 124 of tank 12 c by welding, fasteners, adhesives, or in any other suitable manner. In one embodiment, one attachment device 132 is coupled to a sill 136 that is coupled to tank 12 c. Protective covering 128 may be coupled to attachment bar 132 and brace 134 by welding, fasteners, adhesives, or in any other suitable manner.

[0056] In addition, one or more protective covering supports 138 are disposed between protective covering 128 and exterior surface 134 of tank 12 c. Each protective covering support 128 extends longitudinally along at least a portion of one or more heat transfer ducts 122. Protective covering supports 138 may be formed from one or more heat-resistant materials or materials having low thermal conductivity. Protective covering supports 138 may be coupled to tank 12 c by welding, fasteners, adhesives, or in any other suitable manner.

[0057] An insulating layer 140 is disposed between protective covering 128 and exterior surfaces of heat transfer ducts 122. Insulating layer 140 may be formed from liquid ceramic or ceramic insulating coating (described above with reference to FIG. 3), fiberglass, or any other suitable insulating material. In addition, shielding system 70 c may be formed in a variety of ways. For example, shielding system 70 c may be formed by first applying shielding layer 140 and then coupling protective covering 128 to one or more support structures, such as attachment devices 132 and/or supports 138, or directly to shielding layer 140. As another example, shielding system 70 c may be formed by coupling protective covering 128 to one or more support structures and then inserting or injecting insulation between protective covering 128 and tank 12 c to form shielding layer 140.

[0058]FIG. 6 is a partial cross-section of a tank 12 d and a heating system 50 d of a railway tank car, which is similar to tank 12 and heating system 50 of tank car 10. In addition, FIG. 6 illustrates another embodiment of shielding system 70, indicated as shielding system 70 d. Heating system 50 d includes a plurality of heat transfer ducts 152 coupled to an exterior surface 154 of tank 12 d. Shielding system 70 d includes a heat shield 158 disposed over heat transfer ducts 152 and over nearby or adjacent portions of exterior surface 154 of tank 12 d. Heat shield 158 may be disposed only over components of heating system 50 d and adjacent portions of tank 12 d, rather than over the entire tank 12 d. Thus, in some embodiments, an upper portion of the exterior surface of tank 12 d is substantially free of heat shield 158.

[0059] Heat shield 158 may be coupled to tank 12 d by one or more heat shield supports 162. Each heat shield support 162 may extend longitudinally along at least a portion of one or more heat transfer ducts 152. Heat shield 158 may be coupled to heat shield supports 162, and heat shield supports 162 to tank 12 d, by welding, fasteners, adhesives, or in any other suitable manner. Heat shield 158 may be substantially rigid, and may be formed from one or more heat-resistant materials or materials having relatively low thermal conductivity. In addition, heat shield supports 162 may have similar heat-resistant properties. Shielding systems 70 a through 70 d discussed above with reference to FIGS. 3 through 6 possess many, if not all, of the advantages of shielding system 70 discussed above with reference to FIG. 1.

[0060]FIG. 7 is a partial cross section of a tank 12 e, which is similar to tank 12 of tank car 10, including a heat transfer member for increasing the amount of heat transferred into tank 12 e. A heat transfer duct 182 is coupled to an exterior surface 184 of tank 12 e. A shielding system 188, such as any of shielding systems described above with reference to FIGS. 3 through 6, is coupled to an exterior surface 190 of heat transfer duct 182 and exterior surface 184 of tank 12 e. For example, as shown in FIG. 7, shielding system 188 may include a protective covering 192 and an insulating material 194 disposed between protective covering 192 and exterior surfaces 190 and 184 of heat transfer duct 182 and tank 12 e, respectively.

[0061] A heat transfer member 196 may be coupled to an interior surface 198 of tank 12 e adjacent heat transfer duct 182. Heat transfer member 196 may be operable to increase the amount of heat transfer between the heating fluid inside heat transfer duct 182, indicated by the reference number 200, and an interior compartment 202 of tank 12 e. Heat transfer member 196 may be designed to provide desirable heat transfer rates from heating fluid 200 to interior compartment 202 of tank 12 e. In particular, heat transfer member 196 may have a fin-like shape and may have a large surface area-to-volume ratio. For example, heat transfer member 196 may have a folded, curved, or serpentine configuration to increase the amount of surface area for transferring heat to interior compartment 202 of tank 12 e. Heat transfer member 196 may also be designed to allow easy cleaning of the inside of tank 12 e and/or to minimize the amount of heel that may remain inside tank 12 e after unloading.

[0062] In addition, heat transfer member 196 may be formed from one or more thermally conductive materials, such as steel, aluminum, or an aluminum alloy, for example. Heat transfer member 196 may be coupled to interior surface 198 of tank 12 e by welding, fasteners, adhesives, or in any other suitable manner. In some embodiments, tank 12 e includes a heat transfer member 196 adjacent each heat transfer duct of the particular heating system associated with tank 12 e.

[0063]FIG. 8A is a partial three-dimensional view of a heater panel 300 for use in a heating system for a railway tank car, which is similar to tank car 10. Heater panel 300 includes a sheet 302 and a plurality of dimples 304 extruding from sheet 302. Sheet 302 may be contoured such that heater panel 300 may be coupled to an external surface of a tank, such as discussed below with reference to FIG. 8B. Sheet 302 may be formed from one or more generally non-porous and rigid or semi-rigid materials, such as steel, steel alloys, aluminum, aluminum alloys, plastics, and ceramics, for example.

[0064] Dimples 304 may include holes 306 for welding dimples 304 to an external surface of a tank, such as discussed below with reference to FIG. 8A. In one embodiment, dimples 304 and holes 306 are formed by pressing and punching sheet 302. As shown in the embodiment of FIG. 8A, dimples 304 may be arranged in rows and may be equally spaced. However, dimples 304 may be otherwise arranged, such as in a concentric or random pattern, or such that dimples 304 are aligned with specific locations on the tank, such as for installation purposes.

[0065]FIG. 8B illustrates a heating system 308 including heater panel 300 coupled to a tank 310 (similar to tank 12 of FIG. 1) and a shielding system 312 coupled to heater panel 300. In particular, FIG. 8B is a partial cross-section taken along line 8B-8B of FIG. 8A. As shown in FIG. 8B, heater panel 300 is welded to an exterior surface 314 of tank 310 by welds 316. In particular, dimples 304 are welded to exterior surface 314 of tank 310 at the edges of holes 306. Welds 316 may be formed by welding from outside heater panel 300 through holes 306. It should be noted, however, that heater panel 300 may be otherwise coupled to tank 310, such as with fasteners or adhesives.

[0066] One or more ducts 320 are formed between exterior surface 314 of tank 310 and interior surface 322 of heater panel 300. Ducts 320 are operable to receive heating fluids, such as steam, hot water or hot oil, in order to heat the contents of tank 310, such as described above with reference to heating system 50 of FIG. 1. Heating system 308 may also include one or more inlets and outlets allowing the heating fluid to enter and exit ducts 320.

[0067] Shielding system 312 is coupled to heater panel 300 and may include a protective covering 330 and a shielding layer 332 disposed between protective covering 330 and an exterior surface 334 of heater panel 300. Protective covering 330 is made of any suitable material, such as one or more of the materials discussed above with reference to protective covering 92 of FIG. 4. Shielding layer 332 includes any suitable insulating materials, such as one or more of the materials discussed above with reference to shielding layers 80 and 140 of FIGS. 3 and 5, respectively. In particular, shielding layer 332 may include liquid ceramic or ceramic coating. In some embodiments, protective covering 330 is disposed only over heating system 308 and portions of tank 310 proximate or adjacent to heating system 308, while shielding layer 332 covers all or substantially all of tank 310. It should also be understood that in other embodiments, one or more of the shielding systems, or components thereof, described above with reference to FIGS. 3 through 6 may be used in conjunction with heating system 308.

[0068] Shielding system 312 possess many, if not all, of the advantages of shielding system 70 discussed above with reference to FIG. 1. In particular, shielding system 312 may decrease the amount of heat that is transferred from heating system 308 to the ambient surroundings and increase the amount of heat that is transferred from heating system 308 to the inside of tank 310, which may increase the efficiency of heating system 308. In addition, shielding system 308 may reduce the chance of personnel working on or around tank 310 from being burned or otherwise injured by heating system 308. Shielding system 312 may also protect components of heating system 308, such as heater panel 300, from being physically damaged, such as by personnel working on or around tank 310.

[0069] One or more heater panels 300 may be used to cover large portions, or the entire exterior, of tank 310. Heater panels 300 may also provide additional strength to tank 310 such that desired or required mechanical properties of tank 310 may be achieved using a thinner and/or more lightweight tank wall for tank 310. In addition, or alternatively, heater panels 300 may be disposed on the interior surfaces of tank 310, as described below with reference to FIG. 9.

[0070]FIG. 9 is a partial cross-section illustrating a heating system 340 including a heater panel 342 disposed inside a tank 344 (similar to tank 12 of FIG. 1), and a shielding system 346 coupled to an external surface 348 of tank 344. Heater panel 342 is similar to heater panel 300 discussed above, but heater panel 342 is configured to be coupled to an internal surface 348 of tank 344 rather than an external surface. Thus, heater panel 342 includes a sheet 350 that may have an opposite contour as compared to heater panel 300. In any event, ducts 352 are formed between internal surface 348 of tank 344 and internal surfaces 354 of heater panel 342. Like ducts 320 of FIG. 9B above, ducts 352 are operable to receive heating fluids, such as steam, hot water or hot oil, in order to heat the contents of tank 344, and heating system 340 may include one or more inlets and outlets allowing the heating fluid to enter and exit ducts 352. One or more heater panels 342 may be used to cover large portions, or the entire interior, of tank 344. Using heater panels 342 may also provide additional strength to tank 344 such that desired or required mechanical properties of tank 344 may be achieved using a thinner and/or more lightweight tank wall for tank 344.

[0071] Shielding system 346 may include a protective covering 356 and a shielding layer 358 disposed between protective covering 356 and external surface 348 of tank 344. Protective covering 356 and shielding layer 358 may be similar to protective covering 330 and shielding layer 332, respectively, described above with reference to FIG. 9B. And as noted above with reference to protective covering 330 and shielding layer 332, in some embodiments, protective covering 356 and shielding layer 358 are only disposed over heating system 340, and not over other non-heated portions of tank 344.

[0072] The details of particular embodiments may be determined by evaluating factors such as the desired or required size, strength, weight, capacity, maximum payload, heating ability, or temperature control of the tank car or its contents. Such details include which components to include in the shielding system, such as a shielding layer, a protective cover, or a heat shield, and the appropriate materials and dimensions for each component. In addition, particular embodiments may be selected for holding or transporting a particular product based on factors such as the effect of temperature on the product over time, how the product reacts in tank cars having different shielding systems, whether the product needs to be heated for unloading, and whether changing conditions (such as from highly-viscous to less-viscous or vise versa) has an effect on the quality of the product.

[0073] Although an embodiment of the invention and its advantages are described in detail, a person skilled in the art could make various alternations, additions, and omissions without departing from the spirit and scope of the present invention as defined by the appended claims. 

What is claimed is:
 1. A railway tank car, comprising: a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed end; a plurality of heat transfer ducts disposed on a lower portion of an exterior surface of the tank and operable to receive a heating fluid; and a layer of ceramic coating disposed over exterior surfaces of the plurality of heat transfer ducts.
 2. The railway tank car of claim 1, wherein the layer of ceramic coating extends over at least a portion of the exterior surface of the tank.
 3. The railway tank car of claim 1, wherein the layer of ceramic coating extends over substantially the entire exterior surface of the tank.
 4. The railway tank car of claim 1, wherein an upper portion of the exterior surface of the tank is substantially free of the layer of ceramic coating.
 5. The railway tank car of claim 1, wherein the layer of ceramic coating extends over substantially the entire railway tank car.
 6. The railway tank car of claim 1, wherein the layer of ceramic coating is less than 0.2 inches thick.
 7. The railway tank car of claim 1, wherein at least a portion of the layer of ceramic coating proximate the heat transfer ducts is approximately 0.1 inches thick.
 8. The railway tank car of claim 1, wherein the layer of ceramic coating is relatively thin such that the tank may have a larger diameter without exceeding regulated dimensions of the railcar.
 9. The railway tank car of claim 1, wherein portions of the layer of ceramic coating proximate the heat transfer ducts are thicker than other portions of the layer of ceramic coating.
 10. The railway tank car of claim 1, wherein a layer of paint is disposed over the layer of ceramic coating.
 11. The railway tank car of claim 10, wherein the layer of paint comprises epoxy paint.
 12. The railway tank car of claim 1, further comprising: a protective covering disposed over the exterior surfaces of the plurality of heat transfer ducts such that the plurality of heat transfer ducts are disposed between the protective covering and the exterior surface of the tank; and wherein an upper portion of the exterior surface of the tank is substantially free of the protective cover.
 13. The railway tank car of claim 12, wherein the layer of ceramic coating is substantially covered by the protective cover.
 14. The railway tank car of claim 12, wherein the protective covering is formed from one or more materials selected from the group consisting of steel alloys, aluminum alloys, ceramic materials, cermets, and fiber reinforced plastic.
 15. The railway tank car of claim 12, further comprising at least one support disposed between the exterior surface of the tank and the protective cover.
 16. The railway tank car of claim 1, further comprising: at least one heat transfer member disposed on an interior surface of the tank proximate at least one of the plurality of heat transfer ducts; and wherein the heat transfer member is operable to transfer heat from the heating fluid to an interior compartment of the tank.
 17. The railway tank car of claim 1, wherein the layer of ceramic coating is operable to protect people from being burned by the heat transfer ducts.
 18. A railway tank car, comprising: a tank at least partially defined by a generally elongated hollow cylinder and having a first closed end and a second closed end; a plurality of heat transfer ducts disposed on a lower portion of an exterior surface of the tank and operable to receive a heating fluid; and a heat shield disposed over exterior surfaces of the plurality of heat transfer ducts and portions of the exterior surface of the tank adjacent the heat transfer ducts.
 19. The railway tank car of claim 18, wherein the heat shield is formed from one or more materials selected from the group consisting of steel alloys, aluminum alloys, ceramic materials, cermets, and fiber reinforced plastic.
 20. The railway tank car of claim 18, further comprising a layer of ceramic coating disposed between the heat shield and the exterior surface of the tank.
 21. A railway tank car, comprising: a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed end; one or more heater panels having an interior surface, an exterior surface, and a plurality of dimples; each heater panel being coupled to an exterior surface of the tank by the plurality of dimples such that one or more ducts operable to receive a heating fluid are formed between the interior surface of each heater panel and the exterior surface of the tank; and a layer of ceramic coating disposed on the exterior surface of each heater panel.
 22. The railway tank car of claim 21, further comprising a protective covering disposed over each layer of ceramic coating.
 23. The railway tank car of claim 22, wherein the protective covering is formed from one or more materials selected from the group consisting of steel alloys, aluminum alloys, ceramic materials, cermets, and fiber reinforced plastic.
 24. The railway tank car of claim 21, wherein the one or more heater panels are disposed over substantially the entire exterior surface of the tank.
 25. A railway tank car, comprising: a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed end; one or more heater panels having an interior surface, an exterior surface, and a plurality of dimples; and wherein each heater panel is coupled to an interior surface of the tank by the plurality of dimples such that one or more ducts operable to receive a heating fluid are formed between the interior surface of each heater panel and the interior surface of the tank.
 26. The railway tank car of claim 25, wherein the one or more heater panels are disposed over substantially the entire interior surface of the tank.
 27. A method of shielding a railcar heating system, the method comprising: providing a railway tank car including: a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed end; and a plurality of heat transfer ducts disposed on an exterior surface of the tank and operable to receive a heating fluid; and forming a layer of ceramic coating over exterior surfaces of the plurality of heat transfer ducts.
 28. The method of claim 27, further comprising forming the layer of ceramic coating over at least a portion of the exterior surface of the tank.
 29. The method of claim 27, further comprising forming the layer of ceramic coating over substantially all of the exterior surface of the tank.
 30. The method of claim 27, wherein forming the layer of ceramic coating comprises forming a layer of ceramic coating such that an upper portion of the exterior surface of the tank is substantially free of the layer of ceramic coating.
 31. The method of claim 27, wherein the layer of ceramic coating has a thickness of less than 0.2 inches.
 32. The method of claim 27, wherein the layer of ceramic coating has a thickness of approximately 0.1 inches.
 33. The method of claim 27, wherein portions of the layer of ceramic coating proximate the heat transfer ducts are thicker than other portions of the layer of ceramic coating.
 34. The method of claim 27, wherein forming the layer of ceramic coating comprises spraying ceramic coating over exterior surfaces of the plurality of heat transfer ducts.
 35. The method of claim 27, further comprising installing a protective covering over the layer of ceramic coating, wherein an upper portion of the tank is substantially free of the protective cover.
 36. The method of claim 27, further comprising installing at least one heat transfer member to an interior surface of the tank proximate at least one of the plurality of heat transfer ducts.
 37. A method of shielding a railcar heating system, the method comprising: providing a railway tank car including: a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed end; and one or more heater panels having an interior surface, an exterior surface, and a plurality of dimples; wherein each heater panel is coupled to an exterior surface of the tank by the plurality of dimples such that one or more ducts operable to receive a heating fluid are formed between the interior surface of each heater panel and the exterior surface of the tank; and forming a layer of ceramic coating on the exterior surface of each heater panel.
 38. The method of claim 37, further comprising installing a protective covering over the layer of ceramic coating.
 39. A railway tank car, comprising: a tank at least partially defined by a generally elongated hollow cylinder, a first closed end and a second closed end; a plurality of heat transfer ducts disposed on a lower portion of an exterior surface of the tank and operable to receive a heating fluid; a layer of ceramic coating disposed over exterior surfaces of the plurality of heat transfer ducts and extending over substantially all of the exterior surface of the tank; wherein the layer of ceramic coating is less than 0.2 inches thick; and wherein portions of the layer of ceramic coating proximate the heat transfer ducts are thicker than other portions of the layer of ceramic coating. 